title: Genetic and environmental influences on sodium intake determined by using half-day urine samples: the Healthy Twin Study.
abstract: BACKGROUND
  Salt is essential in our diet, but excess intake is a well-established risk factor for hypertension. The presence and importance of genetic contributions to salt intake, however, are not well understood.
  
  
  OBJECTIVE
  The aim of this study was to examine whether a genetic predisposition and an environmental influence exist for sodium intake and salt habit.
  
  
  METHODS
  In a twin-family cohort, half-day urine samples from 1204 individuals (133 pairs of monozygotic twins, 29 pairs of dizygotic twins, and 880 singletons) were collected to assess 24-h sodium intakes. Daily total sodium intake, sodium density per calorie (Na-D), and salt habit questions were analyzed with adjustment for other epidemiologic characteristics. We calculated heritability (h2) and intraclass correlations to examine the genetic and shared environmental contributions to total sodium intake traits.
  
  
  RESULTS
  The average sodium intake was 208.4 ± 107.0 mmol/d. Men had a higher absolute sodium intake (242.6 ± 117.4 mmol/d), but Na-D did not differ by sex. Moderate genetic influences existed (h2 = 0.31-0.34) for sodium intake and Na-D. We also found that sharing current residence rather than being a family member explained 22% of the variance in Na-D.
  
  
  CONCLUSIONS
  Our findings suggest that both genetic predisposition and shared environment contribute to sodium intakes and salt habits alike.
authors.affiliation: Complex Disease and Genome Epidemiology Branch, Department of Epidemiology, School of Public Health, Seoul National University, Seoul, Korea (MK, SY, and JS); the Department of Food and Nutrition, Sookmyung Women's University, Seoul, Korea (JEL); the Department of Family Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (Y-MS); the Department of Family Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea (KL); the Department of Statistics, Sookmyung Women's University, Seoul, Korea (KK); and the Graduate School of Public Health & Institute of Health and Environment, Seoul National University, Seoul, Korea (HJ).
authors.forename: Minjung
authors.initials: M
authors.lastname: Kho
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Yun-Mi
authors.initials: YM
authors.lastname: Song
authors.forename: Kayoung
authors.initials: K
authors.lastname: Lee
authors.forename: Kyunga
authors.initials: K
authors.lastname: Kim
authors.forename: Sarah
authors.initials: S
authors.lastname: Yang
authors.forename: Hyojee
authors.initials: H
authors.lastname: Joung
authors.forename: Joohon
authors.initials: J
authors.lastname: Sung
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000235:genetics / Q000652:urine; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D056910:Republic of Korea; D012111:Residence Characteristics; D012727:Sex Characteristics; D012964:Sodium / Q000652:urine*; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D055815:Young Adult
chemical_list: D012982:Sodium, Dietary; D012964:Sodium